If you:
- learn a good opening and
- stick with that opening for at least a few years and
- learn main lines (and a few other common lines), but nothing too crazy, like to move 25.
Then sure, I would agree with him... so it's not so controversial I think...
But most beginners do the opposite of those 3 things. They learn some garbage, they learn bad lines of the garbage opening, then a month or a few months later they try to get better results by switching to a new opening.
So lots of people give the very sensible advice that they should ignore openings for a while.
But if you have a GM coach who will spoon feed you good openings, and sensible lines, then sure, study the opening...
... but for 99.99999999% of people this is not how it is.
I like this advise that beginners should study openings: https://www.youtube.com/watch?v=uuDQbMlXeDQ&t=1279s&ab_channel=DanielNaroditsky